He said he watched in horror as the man punched Robert once before he fell to the floor and his head hit the ground with a ‘thud’.

The barman said: “The attacker kicked the inflatable toy and it hit Robert on the back. It was full of mud.

“Robert turned with a bit of a scowl but he then put his hand up to say he did not want trouble.

“The other guy punched him once and he fell to the floor and I heard a thud.

“It was horrible. His girlfriend was screaming and people were waving for help.

“Some of the crowd helped him and gave him chest compressions and then security turned up.

“When they picked him up you could see he was all over the place and his eyes were not right.

“I just knew it was something serious but never thought it would be this bad.”

The barman said the security team did all they could to help Robert, who is from Macclesfield .

He said he witnessed the attack after coming to a stop in the crowd as he tried to make his way home.

The barman has spoken to the police to help with their investigation.

“I really hope they catch him”, he added.

“The atmosphere was good - no different from other festivals I’ve worked at but the few isolated incidents ruined it.”

He said the attack happened as music was played just before headline act Snoop Dogg was due on stage.

Detective Inspector Richard Eales said: "Our immediate thoughts go out to Robert's family and loved ones. We currently have specially trained officers with them to help through this terrible time.

"We are still in the early stages of this investigation. However several witnesses have assisted us with vital information concerning the description of the offender. We believe a confrontation took place following an inflatable doll hitting Robert's girlfriend.

"We are aware other assaults took place in the park that evening but I am specifically appealing for witnesses who recall seeing the inflatable doll and the attack on Robert immediately thereafter.

"I am keen for those witnesses to come forward and other persons nearby who may have mobile phone footage of the attack or captured an image of the person responsible.

"Finally if you are the man responsible or were with him that evening, please come forward."